Seismic sensor systems commonly comprise large arrays of fibre-optic interferometric sensors, such as hydrophones and optionally accelerometers.
From U.S. Pat. No. 7,245,382 it is known that fibre-optic interferometric sensors which are co-located with a reference device such that optical parameters extracted from the reference signal may be used to correct parameters extracted from a sensor signal. In that way, fluctuations in interrogating laser frequency and fluctuations in delay of compensating interferometers (where such are used), may be compensated.
Sensitivity of the reference sensors to environmental parameters may lead to cross-sensitivity to the environmental parameters of the reference corrected sensor signals. However, it is challenging and expensive to completely isolate the reference sensors from fluctuations in environmental parameters such as pressure, acceleration, temperature.
Hence, an improved fibre-optic interferometric sensor system would be advantageous, and in particular a more efficient and/or reliable method of compensating measured signals for noise and/or cross-sensitivity would be advantageous.